This week Jonathan chats with Toke Hoiland-Jorgensen about CAKE_MQ, the newest Kernel innovation to combat Bufferbloat! What was the realization that made CAKE parallelization? When can we expect it in the wild? And what’s new in the rest of the kernel world? Watch to find out!
Continue reading “FLOSS Weekly Episode 862: Have Your CAKE And Eat It Too”
If you’re an old-schooler, you might still go to the local bar and pay for a beer with cash. You could even try and pay with a cheque, though the pen-and-paper method has mostly fallen out of favor these days. But if you’re a little more modern, you might use a tap-to-pay feature on a credit or debit card.
In Taiwan, though, there’s another unique way to pay. The island nation has a whole ecosystem of bespoke payment cards, and you can even get one that looks like a floppy disk!
We know that while the cost per byte of persistent storage has dropped hugely over the years, it’s still a pain to fork out for a new disk drive. This must be why [MadAvidCoder] has taken a different approach to storage, placing files as multiple encoded pieces of metadata in Wikipedia edits.
The project takes a file, compresses it, and spits out small innocuous strings. These are placed in the comments for Wikipedia edits — which they are at pains to stress — were all legitimate edits in the test cases. The strings can then be retrieved at will and reconstituted, for later use. The test files are a small bitmap of a banana, and a short audio file.
It’s an interesting technique, though fortunately one that’s unlikely to be practical beyond a little amusement at the encyclopedia’s expense. We probably all have our favorite examples of low quality Wikipedia content, so perhaps it’s fortunate that these are hidden in the edit history rather than the pages themselves. Meanwhile we’re reminded of the equally impractical PingFS, using network pings as a file system medium.
While it has become a word, laser used to be an acronym: “light amplification by stimulated emission of radiation”. But there is an even older technology called a maser, which is the same acronym but with light switched out for microwaves. If you’ve never heard of masers, you might be tempted to dismiss them as early proto-lasers that are obsolete. But you’d be wrong! Masers keep showing up in places you’d never expect: radio telescopes, atomic clocks, deep-space tracking, and even some bleeding-edge quantum experiments. And depending on how a few materials and microwave engineering problems shake out, masers might be headed for a second golden age.
Simplistically, the maser is — in one sense — a “lower frequency laser.” Just like a laser, stimulated emission is what makes it work. You prepare a bunch of atoms or molecules in an excited energy state (a population inversion), and then a passing photon of the right frequency triggers them to drop to a lower state while emitting a second photon that matches the first with the same frequency, phase, and direction. Do that in a resonant cavity and you’ve got gain, coherence, and a remarkably clean signal.
Home automation with high usefulness and low annoyance tends to rely on reliable person sensing, and [francescopace]’s ESPectre shows one way to do that cheaply and easily by leveraging hardware that’s already present on a common dev board.
ESPectre is an ESP32-based open source motion detector that detects movement without any cameras or microphones. It works similarly to millimeter-wave (mmWave) radar motion detectors in the sense that when a person moves, wireless signals are altered slightly as a result. ESPectre can detect this disturbance by watching and analyzing the Wi-Fi channel state information (CSI) and doing some very smart math and filtering. It’s cheap, easy to deploy and use, and even integrates with Home Assistant.
Combining a sensor like this with something else like a passive infrared (PIR) motion sensor is one way to get really robust results. But keep in mind that PIR only senses what it can see, whereas ESPectre works on WiFi, which can penetrate walls.
Since ESPectre supports low-cost ESP32 variants and is so simple to get up and running, it might be worth your time to give it a trial run. There’s even a browser-based ghost-dodging game [francescopace] put online that uses an ESPectre board plugged in over USB, which seems like a fun way to get a feel for what it can do.
If your travels take you near Mountain View, California, you can have the pleasure of visiting the Computer History Museum. You can see everything from a PDP-1 to an Altair 8800 to a modern PC there. If you aren’t travelling, the museum has launched a digital portal that expands your ability to enjoy its collection remotely.
CEO Marc Etkind said, “OpenCHM is designed to inspire discovery, spark curiosity, and make the stories of the digital age more accessible to everyone, everywhere. We’re unlocking the collection for new audiences to explore.”
The portal features advanced search tools along with browsable curated collections and stories. There’s also an album feature so you can create and share your own custom collections. If you are a developer, the portal also allows access via an API.
As an example, we checked out the vintage marketing collection. Inside were a 1955 brochure for a Bendix computer you could lease for under $1,000 a month, and a 1969 brochure for the high-performance Hitachi HITEC 10. It had 4K words of 16-bit memory and a clock just a bit more than 700 kHz, among others.
If you are on the other side of the Atlantic, you might want to check out a very large museum there. There’s also a fine museum in the UK.
Decades ago, shows like Star Trek, The Jetsons, and Lost in Space promised us a future full of helpful computers and robot assistants. Unfortunately, we haven’t quite gotten our general-purpose helper to do all of our tasks with a simple voice command yet. But if some sweat equity is applied, we can get machines to do specific tasks for us under some situations. [Max Maker] built this remote-controlled lawnmower which at least minimizes the physical labor he needs to do to cut his grass.
The first step in the project was to remove the human interface parts of the push mower and start working on a frame for the various control mechanisms. This includes adding an actuator to raise and lower the mower deck on the fly. Driving the new rear wheels are two wheelchair motors, which allow it to use differential steering, with a set of casters up front for maximum maneuverability. An Arduino Mega sits in a custom enclosure to control everything and receive the RC signals, alongside the mower’s batteries and the motor controllers for the drive wheels.
After some issues with programming, [Max] has an effective remote controlled mower that he can use to mulch leaves or cut grass without getting out of his chair. It would also make an excellent platform if he decides to fully automate it in the future, which is a project that has been done fairly effectively in the past even at much larger scales.
